The conventional terminal gear for checking tooth contact in which a conductive material and an insulating material are laminated parallel to the flat sides of the tooth, is capable of checking the tooth contact in one direction, but unable to do so in a direction perpendicular thereto. Moreover, in the case of a conventional laminated master gear in which the distance between the conductive laminations must be at least 1 mm on account of the technical limitations for alternately laminating the metal conductor and insulating material, it is difficult to make an inspection of the tooth contact even in said one direction with sufficient precision. Furthermore, a conventional laminated master gear, which is usually insulated with resin, is subject to a considerable drop in the precision of checking due to the thermal expansion or thermal deformation of the resin used and it has been necessary to use the gear at a controlled temperature. For these reasons a conventional master gear for checking tooth contact is unsatisfactory for the mass-production of gears with high dimensional precision. Thus there has been a strong demand for the development of a master gear for checking tooth contact which can check the tooth contact both in a direction parallel to the flat side of the tooth and one perpendicular thereto at the same time, which can carry out the checking with higher precision, and can be unaffected by the temperature of the surroundings in which it is used.